“Most of these never come into your house, they just live in the bush and they play a vital role in breaking down nutrients and leaf litter, and pollinating plants,” Mr Fearn said.

“Just a handful of urban, introduced cockroaches are giving the whole group a bad name, whereas the majority are actually doing us a service.”

The new species have never been recognised by science before because no one ever noticed them, Mr Fearn said.

“They have yet to be formally described by a taxonomist.”

That was when new species were given a scientific name after a taxonomist compared the species with all other specimens of species, which was a lengthy, scientific process.

It was a crucial point as it meant it would be established and recognised as a new species by the scientific community

“As you can imagine, there are not a lot of taxonomists in the world who specialise in cockroaches.”

He estimated only two or three people in the world, and only one in Australia, who were able to scientifically describe cockroaches as someone needed to have a comprehensive knowledge of the entire species.

“We are constantly finding cockroaches in our field work that have yet to be named.”

It might take years for any of them to be named, Mr Fearn said.

He has also discovered several mainland cockroaches in Tasmania after they hitching a ride across Bass Strait.

As for the other critters he has found in his quarter acre block, Mr Fearn said he has already documented 700 different species.

“At the rate tropical forests are being cleared around the world, there would be no question that there would be lots and lots of insects becoming extinct.”